Method of fabricating patterned tubing from metallic strip

ABSTRACT

A method of fabricating tubing having formed patterns in or upon the tubing wall where the formed pattern is interrupted by contiguous wall sections or segments which are free of said formed pattern facilitating the manufacture of discrete tube lengths having smooth or patterned wall structure in any desired continuity or configuration.

[ Nov. 11, 1975 v [75] Inventor:

[ 1 METHOD OF FABRICATING PATTERNED TUBING FROM METALLIC STRIP CharlesD. McLain, Alton, Ill.

[73] Assignee: Olin Corporation, New Haven,

Conn.

[22] Filed: May 10, 1973 21 Appl. No.: 359,019

Related US. Application Data [63] Continuation-impart of Ser. Nos.214.034. Dec. 30. 1971, abandoned, and Ser. No. 218.422. Jan. 17. 1972,abandoned.

[52] US. Cl. 228/147; 228/152; 219/67; 72/196; 72/368 [51] Int. Cl. B21C37/08 Field of Search 29/477.7, 477, 157.3 R; 219/85, 67; 72/196,366-368; 228/144, 146, 147, 17.5, 152

[56] References Cited UNlTED STATES PATENTS 1.211.460 1/1917 Lindquist72/196 CUT 1.522.963 1/1925 Matthews 29/477 1.811.678 6/1931 2.265.12912/1941 Darner 2.641.830 6/1953 Lamb et a1 3.165.815 1/1965Wogerbauer....

3,407,638 10/1969 Greis et a1. 72/96 3.831.675 8/1974 McLain 29/477 XPrimary E.\'aminerAl Lawrence Smith Assistant E.\'aminerK. J. RamseyAttorney, Agent, or FirmRobert H. Bachman [5 7 ABSTRACT A method offabricating tubing having formed patterns in or upon the tubing wallwhere the formed pattern is interrupted by contiguous wall sections orseg ments which are free of said formed pattern facilitating themanufacture of discrete tube lengths having smooth or patterned wallstructure in any desired continuity or configuration.

8 Claims, 12 Drawing Figures CUT US. Patent N0v.11, 1975 Sheet10f43,918,626

U.S. Patent Nov. 11, 1975 Sheet 2 Of4 3,918,626

US. Patent Nov. 11,1975 Sheet 3 014 3,918,626

TUBE FORMING MILL STRIP SUPPLY I U .S. Patent Nov.1 1,1975 Sheet40f43,918,626

WELD

BEAD REMOVAL WE L DING 5 TA T/ON SHAPING AND OR S/Z/NG TUBE F ORM/N G STR/P CORRUGA T/NG SEPA RA TING STA T/O/V S TR/P SUPPLY cur METHOD OFFABRICATING PATTERNED TUBING FROM METALLIC STRIP CROSS REFERENCE TORELATED APPLICATIONS This application is a Continuation-In-Part ofcopending applications Ser. No. 214,034, filed Dec. 30, 1971, and Ser.No. 218,422. filed Jan. I7, 1972, by Charles D. McLain, both nowabandoned.

BACKGROUND OF THE INVENTION This invention relates to the continuousfabrication of tubing using metallic strip as a starting material.

For example, metallic strip of predetermined width tube formingprocesses which include continuously embossing one or more surfaces ofthe strip in accordance with any desired pattern prior to entry into thetube mill so that the tubing ultimately formed has an embossed surfaceon the interior orthe exterior or both surfaces of the tube wall asdesired. Obviously, the pattern structure is a matter of choiceconsistent with the ultimate use of the tubing.

The co-pending applications are also directed to physically andcontinuously deforming the strip, prior to entry into the tube mill, bygenerating longitudinal, spiral or transverse striations, grooves orchannels in the strip. Thus, the tube ultimately fabricated fromdeformed strip has a wall structure which has been physically shaped inone fashionor another in contrast to tube wall structure developed fromembossed strip. Here again, the pattern generated by deforming the stripis a matter of choice governed by ultimate tube use.

Accordingly, the co-pending applications deal with tubing made fromstrip formed with a pattern by embossing, etching or similar surfacetreatment or with tubing made from strip formed with a pattern bycorrugating, crimping or other metal formimg process.

The co-pending applications also disclose that in the case of stripsurface treatment a pattern may be generated on one or more sides of thestrip so that the wall of the tube ultimately formed may carry a patternon the internal wall surface or the external .wall surface or on bothwall surfaces, as desired.

Obviously, if the pattern is generated by deforming the strip, it willappear on the interior as well as the exterior of the tube wall. 1

For purposes of claiming the present invention surface treatments on oneor more sides of the strip or deformation of the strip, which generatediscernable surface indicia or which generate deformed wall structure inthe tubing, are all referred to as formed pattern,

pattern forming," or pattern.

The method of developing the pattern by surface treatment or the methodof developing the pattern by deforming the strip are a matter of choiceand are not critical to the principles of the present invention.

Therefore, it is to be understood that the language process or operationwhich removes metal from any surface of the strip or which physicallydeforms the strip prior to entry into the tube mill.

Obviously. the term patternis intended to define the result of suchmetal removal or metal deformation.

SUMMARY OF THE INVENTION It is a principal object ofthe presentinvention to provide a process for fabricating discrete lengths oftubing having wall segments or sections defining formed patternsinterruped by contiguous wall segments which are smooth or free of saidformed pattern.

It is an additional object of the present invention to provide animproved process for continuously fabricating tubing from metallic stripwhere discrete lengths of tubing are formed with discontinuous patternsin vari' ous combinations and permutations and the discontinuities areexemplified by intervening and contiguous tube segmentswhich are smoothor free of a pattern.

It is a further object of the invention to provide an improvedcontinuous process for generating tubing from metallic strip where thetubing fabricated has a wall formed with a pattern interrupted bycontiguous wall segments which are smooth or free of a formed pattern,giving one the option to separate the tubing into discrete lengths inthe region ofa pattern or in the region of a smooth segment.

A process embracing certain principles of the present invention maycomprise the steps of: providing a strip of metal of predeterminedwidth, indefinite lengths and side edges; continuously advancing thestrip; continuously forming patterns on at least one surface of thestrip during the course of advance; intermittently interrupting thepattern forming step to break the continuity of the formed pattern andto create intervening smooth segments in said surface defining adiscontinuous pattern; continuously forming said strip into a tube byabutting the side edges to create a seam; continuously closing the seamto create a fluid-tight seal; and thereafter continuously separting thetubing into discrete lengths, said separating step occurring in theregions of the tube defined by said smooth segments.

tion with the appended drawings, in which:

applied to the metallic strip is intended to include any BRIEFDESCRIPTION OF DRAWINGS pattern is interrupted by a smooth wall;

FIG. 8 shows a typical tube forming die; FIG. 9 is a side view of a millarrangement operative to generate patterns on the strip in discontinuousfash- FIG. 10 shows, schematically, a typical tube forming operationstarting with the strip supply and ending with tube cutting orseparation;

FIGS. l1 and 12 illustrate points at which the tube may be separated orcut into discrete lengths.

Referring now to FIGS. 1, 2 and 3, the reference numeral l designates afinished length of tubing having smooth ends 11 and I2 and anintermediate patterned segment 13. In this case, the internal surfaceofthe tube I4 is smooth throughout.

FIG. 2 shows a length of tubing having a smooth external surface 16throughout its length with an interior patterned surface I7 terminatingin smooth ends 18 and I9.

FIG. 3 shows a still further variation in that tube 20 is formed with apattern 21 throughout its interior and the exterior surface is smooth asat 22 and patterned at each end as indicated by the reference numerals23 and 24.

FIGS. 4 and 5 each illustrate a pair of cooperating mill rolls, 26-27and 28-29 operative to form a pattern "P on one or both surfaces ofstrip 5 as disclosed in said co-pending applications.

FIG. 6 shows mill rolls 31-32 operative to physically deform strip S bygenerating striations or corrugations indicated by the reference numeral33, also disclosed and described in the co-pending applications.

In FIG. 7, a discrete length of tubing 34 is formed,

' length'of pattern that one desires to generate) to move from anoperative position indicated by the reference numeral 49 to aninoperative position indicated by the reference numeral 51.Byappro'priate control or programming of the operative and inoperativecondition of the various pairs of mill rolls, one can generate a brokenor interrupted pattern on the strip in accordance 'with variouscombinations or permutations.'as desired.

For example. a discontinuity of pattern can be generated on the bottomsurface 52 of the strip leaving the top surface 53 smooth, or viceversa.

Obviously, if one surface or the other is intended to be smooththroughout, a smooth roll must be placed in working contact with thatsurface.

Furthermore. with appropriate programming. the pattern forming mill Mcan be operated to generate pattern discontinuites in top and bottomsurfaces of the strip (interior and exterior surfaces of tubing) whichare phased (or displaced) from one another so that a particular tubesegment ultimately formed can be smooth (or formed with a pattern) onboth surfaces in a particular selected segment or a pattern can bedisplaced on one surface relative to the pattern on the oppositesurface. Thus. smooth and patterned tube segments on the interior andexterior surfaces of a given length of tubing can be phased or displacedas design considerations in the ultimate use of the tube dicatate.

For example, FIG. 3 shows a displaced pattern in that segment 22 on theexterior surface of the tube 20 is smooth, while the interior surface 21is formed with a pattern throughout without any discontinuity. Incontrast. the window 50in FIG. 1i illustrates a phased pattern.

Frequently it is necessary to size the strip before its entry into thetube mill to insure a neat. uniform longitudinal seam. Typically thisinvolves scarfing. bevelling or shearing the side edges of thestripstarting material to create a uniform cross-sectional configuration inthe strip before entry into the tube mill.

It is to be understood that the process steps of the present inventioncan be praticed on virtually any metallic strip which is susceptible ofpattern forming.

Furthermore. while one principal use of tubing fabricated in accordancewith the principles of the invention involves heat exchangerapplications, it entirely within the scope of the invention to utilizethe exterior ornamentation and aesthetic design features of the finishedtubing in applications other than in the field of heat exchangers.

It is anticipated that a variety of pattern modifications maybe devisedas considerations of thermal engineering. construction and ornamentationmay dictate without departing from the spirit and scope of theinvention.

What is claimed is:

I. A method of continuously fabricating metallic tubing having formedpatterns on the tubing wall comprising the steps of:

providing a strip of metal of predetermined width. in-

definite length and side edges; continuously advancing the strip;continuously forming patterns on at least one surface of the stripduring the course of advance;

intermittently interrupting the pattern forming step to break thecontinuity of the formed pattern and to create intervening smoothsegments in said surface transverse to the strip length. each segmentbeing a discontinuity in the pattern across the width of the strip;

continuously forming said strip into -a tubeby abutting the side edgesto create a longitudinal, axially extending, continuous seam;

continuously welding said seam to create a fluid-tight seal;

and thereafter transversely cutting the tubing within smooth segmentsthereofinto discrete tube lengths.

2. The method of fabricating tubing according to claim 1 in which thetube cutting step occurs within segments having a smooth internalsurface.

3. The method of fabricating tubing according to claim I in which thepattern forming step occurs on opposite surfaces of the strip.

4. The method of fabricating tubing according to claim I in which thepattern forming step occurs on opposite surfaces of the stripsimultaneously and the interruption step is timed so that the patterndiscontinuity on one surface is phased with the correspondingdiscontinuity on the second surface.

5. The method of fabricating tubing according to claim I in which thepattern forming step occurs on opposite surfaces of the stripsimultaneously and the interruption step is timed so that the patterndiscontinuity on one surface is displaced with respect to thecorresponding discontinuity on the second surface.

6. The method of claim I wherein the intermittent interruption of thepattern forming stepto break continuity of the formed pattern isaccomplished by shifting from one pattern configuration to anotherpattern configuration.

7. A method according to claim 1 in which the pattern forming stepcomprises forming longitudinally extending corrugations.

8. A method according to claim 1 in which the tube cutting step occurswithin segments having a smooth external surface.

1. A method of continuously fabricating metallic tubing having formedpatterns on the tubing wall comprising the steps of: providing a stripof metal of predetermined width, indefinite length and side edges;continuously advancing the strip; continuously forming patterns on atleast one surface of the strip during the course of advance;intermittently interrupting the pattern forming step to break thecontinuity of the formed pattern and to create intervening smoothsegments in said surface transverse to the strip length, each segmentbeing a discontinuity in the pattern across the width of the strip;continuously forming said strip into a tube by abutting the side edgesto create a longitudinal, axially extending, continuous seam;continuously welding said seam to create a fluid-tight seal; andthereafter transversely cutting the tubing within smooth segmentsthereof into discrete tube lengths.
 2. The method of fabricating tubingaccording to claim 1 in which the tube cutting step occurs withinsegments having a smooth internal surface.
 3. The method of fabricatingtubing according to claim 1 in which the pattern forming step occurs onopposite surfaces of the strip.
 4. The method of fabricating tubingaccording to claim 1 in which the pattern forming step occurs onopposite surfaces of the strip simultaneously and the interruption stepis timed so that the pattern discontinuity on one surface is phased withthe corresponding discontinuity on the second surface.
 5. The method offabricating tubing according to claim 1 in which the pattern formingstep occurs on opposite surfaces of the strip simultaneously and theinterruption step is timed so that the pattern discontinuity on onesurface is displaced with respect to the corresponding discontinuity onthe second surface.
 6. The method of claim 1 wherein the intermittentinterruption of the pattern forming step to break continuity of theformed pattern is accomplished by shifting from one patternconfiguration to another pattern configuration.
 7. A method according toclaim 1 in which the pattern forming step comprises forminglongitudinally extending corrugations.
 8. A method according to claim 1in which the tube cutting step occurs within segments having a smoothexternal surface.